• Journal of Sensor Science and Technology
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• v.32 no.2
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• pp.88-94
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• 2023

Recently, piezoelectric tactile sensors have garnered considerable attention in the field of texture recognition owing to their high sensitivity and high-frequency detection capability. Despite their remarkable potential, improving their mechanical flexibility to attach to complex surfaces remains challenging. In this study, we present a flexible piezoelectric sensor that can be bent to an extremely small radius of up to 2.5 mm and still maintain good electrical performance. The proposed sensor was fabricated by controlling the thickness that induces internal stress under external deformation. The fabricated piezoelectric sensor exhibited a high sensitivity of 9.3 nA/kPa ranging from 0 to 10 kPa and a wide frequency range of up to 1 kHz. To demonstrate real-time texture recognition by rubbing the surface of an object with our sensor, nine sets of fabric plates were prepared to reflect their material properties and surface roughness. To extract features of the objects from the detected sensing data, we converted the analog dataset to short-term Fourier transform images. Subsequently, texture recognition was performed using a convolutional neural network with a classification accuracy of 97%.

• Journal of the Korea Convergence Society
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• v.12 no.6
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• pp.107-112
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• 2021

The purpose of this to study a more accurate scoring method in accordance with the change in the game due to the fast-break and external shots of modern basketball. We will make to design and develop a smart basketball device with a digital pressure sensor. The basketball is a sport that combines complex techniques such as dribbling, passing, and shooting, and the game wins or loses with the most goals in all sports on the planet. In particular, shooting, which determines the win or loss of a game, is the technique that is most directly linked to the score, so the angle of projection is important to make a more accurate shooting. The purpose of this to develop an assistive device in order for the player to have a certain shooting rhythm by measuring the throw angle through a sensor that can measure the throw angle of the ball during shooting. This smart basketball device, it is possible to increase the accuracy of shooting through a certain throw angle at the basketball game field or during shooting practice, and accordingly, the performance can be expected to improve.

• Journal of Sensor Science and Technology
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• v.12 no.1
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• pp.44-50
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• 2003

A security system consisted of an infrared sensor and PLD(Programmable Logic Device) was fabricated to prevent an intruder. The fabricated system detect the intruder using infrared sensor and has password key pad to permit someone to enter the house and office. The control circuit of the system is designed by VHDL(Very high speed integrated Hardware Description Language). The system was demonstrated in various conditions and the output signals were displayed in LCD, LED, buzzer and so on. This designed system in this paper has a advantage to supplement additional function with ease.

• Laser Solutions
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• v.13 no.2
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• pp.17-23
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• 2010

It is very important to track a complicate weld seam for the welding automation. Very recently, laser vision sensor becomes a useful sensing tool to find the seams. Until now, however studies of welding automation using a laser vision sensor, focused on either image processing or feature recognition from CCD camera. Even though it is possible to use a simple algorithm for tracking a simple seam, it is extremely difficult to develop a seam-tracking algorithm when the seam is more complex. To overcome these difficulties, this study introduces a simulation system to develop the seam tracking algorithm. This method was verified experimentally to reduce the time and effort to develop the seam tracking algorithm, and to implement the sensing device.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.11
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• pp.857-861
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• 2012

FPN (fixed-pattern-noise) mainly comes from the device or pattern mismatches in pixel and color filter, pixel photodiode leakage in CMOS image sensor. In this paper, optical stack module related pixel FPN was investigated and the classification of pixel FPN contribution with the individual optical module process was presented. The methodology and procedure would be helpful in reducing the greater pixel FPN and distinguishing the complex FPN sources with respect to various noise factors.

• Smart Structures and Systems
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• v.1 no.4
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• pp.325-338
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• 2005

Utilizing robotic based reconfigurable nodal structural health monitoring systems has many advantages over static or human positioned sensor systems. However, creating a robot capable of traversing a variety of civil infrastructures is a difficult task, as these structures each have unique features and characteristics posing a variety of challenges to the robot design. This paper outlines the design and implementation of a novel robotic platform for deployment on ferromagnetic structures as an enabling structural health monitoring technology. The key feature of this design is the utilization of an attachment device which is an advancement of the common magnetic base found in the machine tool industry. By mechanizing this switchable magnetic circuit and redesigning it for light weight and compactness, it becomes an extremely efficient and robust means of attachment for use in various robotic and structural health monitoring applications. The ability to engage and disengage the magnet as needed, the very low power required to do so, the variety of applicable geometric configurations, and the ability to hold indefinitely once engaged make this device ideally suited for numerous robotic and distributed sensor network applications. Presented here are examples of the mechanized variable force magnets, as well as a prototype robot which has been successfully deployed on a large construction site. Also presented are other applications and future directions of this technology.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.999-1007
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• 2012

Multi-precision multiplication over public key cryptography should be considered for performance enhancement due to its computational complexity. Particularly, embedded device is not suitable to execute high complex computation, public key cryptography, because of its limited computational power and capacity. To overcome this flaw, research on multi-precision multiplication with fast computation and small capacity is actively being conducted. In the paper, we explore the cutting-edge technology of multi-precision multiplication for efficient implementation of public key cryptography over sensor network. This survey report will be used for further research on implementation of public key cryptography over sensor network.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1272-1278
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• 2022

The government enacted and promulgated the 'Severe Accident Punishment Act' in January 2021 and is implementing this law. However, the number of occupational accidents in 2021 increased by 10.7% compared to the same period of the previous year. Therefore, safety measures are urgently needed in the industrial field. In this study, BLE Mesh networking technology is applied for safety management of high-risk industrial sites with poor communication environment. The complex sensor AIoT device collects gas sensing values, voice and motion values in real time, analyzes the information values through artificial intelligence LSTM algorithm and CNN algorithm, and recognizes dangerous situations and transmits them to the server. The server monitors the transmitted risk information in real time so that immediate relief measures are taken. By applying the AIoT device and safety management system proposed in this study to high-risk industrial sites, it will minimize industrial accidents and contribute to the expansion of the social safety net.

• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.343-348
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• 2012

ZigBee Network is enabling technology for home automation, surveillance and monitoring system. For better secure network environment, secure and robust security model is important. The paper proposes an application, attribute-based proxy re-encryption on ZigBee networks. The method can distribute the authority to designated sensor nodes to decrypt re-encrypted ciphertext with associated attributes. However, a previous method is required to compute complex pairing operations. The high complexity is not suited to low resource device sensor networks, and it does not provide routing security either. To resolve these problems, we present a novel mechanism. The method can reduce overhead by imposing overhead to full function devices and ensure routing paths as well.

• Journal of Advanced Navigation Technology
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• v.11 no.4
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• pp.408-414
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• 2007

Research advances in the areas of micro-sensor device and wireless network technology, has made it possible to develop energy efficient and low cost wireless sensor nodes. In this paper, the forward error control (FEC) scheme for lower power consumption and excellent BER(Bit Error Rate) performance during transmission propose in multi-hop wireless sensor network based on FSK modem. The FEC technique uses extra processing power related to encoding and decoding, it is need complex functions to be built into the sensor node. The probability of receiving a correct bit and codeword for relaying a frame over h nodes to the sink node is calculated as a function of channel parameter, number of hops, number of bits transmitted and the distance between the different nodes.